Obesity, which is defined in general terms as an excess of body fat relative to lean body mass, is now a world wide epidemic, and is one of the most serious contributors to increased morbidity and mortality. Obesity is prevalent in the United States, affecting more than 61% of the total population (Flegal, et al., Overweight and Obesity in the United States: Prevalence and Trends, 1960-1994. Int J Obes 22:39-47, 1998). Obesity is defined more specifically by the United States Centers for Disease Control and Prevention (CDC) as an excessively high amount of body fat or adipose tissue in relation to lean body mass and overweight is defined as an increased body weight in relation to height, when compared to some standard of acceptable or desirable weight. The CDC alternatively defines overweight as a person with a body mass index (BMI) between 25.0 and 29.9 and obesity is defined as a BMI greater than or equal to 30.0. Obesity is often associated with psychological and medical morbidities, the latter of which includes increased joint problems, vascular diseases such as coronary artery disease, hypertension, stroke, and peripheral vascular disease. Obesity also causes metabolic abnormalities such as insulin resistance and Type II diabetes (non-insulin-dependent diabetes mellitus (NIDDM)), hyperlipidemia, and endothelial dysfunction. These abnormalities predispose the vasculature to injury, cellular proliferation and lipid oxidation, with resulting atherosclerosis leading to heart attack, stroke, and peripheral vascular diseases. In 1998, consumers spent $33 billion in the United States for weight-loss products and services with a less than positive outcome (Serdula, et al., Prevalence of Attempting Weight Loss and Strategies for Controlling Weight, JAMA 282:1353-1358, 1999). Thus, obesity and its associated complications continue to be a major problem throughout the worldwide health care system.
Obesity is clearly an important clinical problem with very broad reaching implications. There is a pressing need for more research on the molecular mechanisms that underlie obesity and its medical consequences, as well as new approaches for its treatment. To date, these approaches have been limited to diet and exercise (therapeutic lifestyle changes), surgical procedures such as gastric bypass, and pharmacologic agents. Drug treatment for obesity has been disappointing since almost all drug treatments for obesity are associated with undesirable side effects that contributed to their termination. A number of monoamines and neuropeptides are known to reduce food intake (Bray, et al., Pharmacological Treatment of Obesity, Am J Clin Nutr 55:151S-319S, 1992). Available pharmacotherapies have included Sibutramine (an appetite suppressant), Orlistat (a lipase inhibitor), fenfluramine and dexfenfluramine. Although body weight loss is effective, these sympathomimetic drugs cause side effects including pulmonary hypertension, neuroanatomic changes, and atypical valvular heart diseases. For example, fenfluramine and dexfenfluramine were withdrawn from the market in 1997 because of associated cardiac valvulopathy (Connolly, et al., Valvular Heart Disease Associated With Fenfluramine-Phentermine, New Engl J Med 337-581-588, 1997). Thus, nutrition and dietary restriction are most desirable for weight loss. However, long-term success of dietary regulation is low because of noncompliance. The loss of motivation to change dietary habits necessary to consume less fat and fewer calories results in regaining weight.
Thus, there are no real treatments based on the biology of the primary metabolic abnormalities found in obesity and its related conditions, such as metabolic syndrome or atherosclerosis. Accordingly, there is still a need for new compositions and methods that address treating individuals suffering from obesity and obesity-related disorders. There is also a need for new agents and compositions for treating individuals infected with human immunodeficiency virus (HIV). It is toward the development of new compositions and methods for treating obesity and obesity-related disorders and for treating individuals infected with HIV that the present invention is directed.
The citation of any reference herein should not be construed as an admission that such reference is prior art to the instant invention.